The properties panel displays the most relevant information of the selected object (diagram, object, or diagram). 

This is the main diagram canvas, where objects are placed and interconnected. Select the diagram (click in the white space), an object or a connection to display it's properties 

This section display the object's properties (name and description). Use the Edit link to change object properties.

This section displays the object's parameters. It is only displayed for processes, as these have actions with parameters.